Please note that the new version on the server requires a new version in your client, you can find the update here...
Also note that the update resets your client key settings and other preferences (not your saved server addresses though ,

This new version isnt backwards compatible but adds a load of new features - including the oft requested External Radio mode.
This allows radios to be used WITHOUT DCS running as long as you've got the password and it's been turned on by the server admin.